As l stated before, if you reject Genesis 1:1, you reject the whole Bible.
No, I accept the bible as a collection of ancient texts about various things by various authors at various times and places, remarkably well preserved and full of insights into one branch of ancient thought. Some of the purported history is accurate, some is not. There may not have been an Egyptian captivity or a Moses, according to the archaeology, for example.
If you find it hard to believe that Mary was a virgin when she conceived
Unless she was only partly a she, there's no way, even with a very rare example of parthenogenesis, that she could have born a boy.
then you'll also reject Noah's building of the Ark
The evidence against a real worldwide Noah's Flood is overwhelming, unignorably huge.
Abraham having a son, Joseph's dream interpretations, Moses' signs and wonders etc etc.
Each needs to be looked to work out what it's about, but basically, yes, none of that is literally true.
Then, of course, we have a New Testament full of miracles, not least the resurrection.
Yes, I don't believe in magic, and the resurrection is not only magic, but as a report some or other ancient mystery, a forensic disaster, with no eyewitness, no contemporary report, no independent report. That's apart from innately having no credibility.
Take all these out and you're left with a meaningless account that has no consistency or coherence. It's been attempted by some historians and fails miserably.
Yes, it's not coherent because it was no more meant to be a unitary tale than the classifieds of the New York Times ─ each part has its own author or authors and their own purposes. But like the New York Times classifieds, the writers are writing within a tradition.
IMO, what is written in the Bible is a prophecy, inspired by God. To suggest that men concocted the stories infers that they had reason to lie and deceive others.
Perhaps they did, but there's no necessity for such a conclusion. Way back then all the Canaanite tribes had their gods, largely within the Semitic tradition. At the start of the bible, Yahweh is simply one of them, thought by his followers to be the most powerful, though I dare say each tribe thought its god the most powerful.
So what was their motivation, and how did they collude over 1500 years to produce this lie?
It isn't a lie to them. It's what you do, it's how you account for the weather, the famines, the plagues, good and bad luck at hunting fishing love and war, birth, death, and so on. We find supernatural beings of various kinds in virtually all cultures ─ they're clearly an artifact of how our brains have evolved, presumably to do with our curiosity and craving for explanations, and our instincts for tribal identity and solidarity with shared language, customs, heroes, stories and religions.
Josephus wrote his 'Antiquities' in an historical style but it's noticeable that he did not extract the miracles and wonders from his account of lsrael's Exodus from Egypt.
The first writer of history to use what we'd say was early historical method was Herodotos in the 5th century BCE, sharpened very shortly after by Thucydides. Up till then there was often little difference between history and story. Clearly the NT authors, despite their training in Greek, did not use historical method.